\documentclass[border=5]{standalone}
\usepackage{tikz}
\newbox\stereogrambox
\pgfmathdeclarerandomlist{colors}{{red}{green!50!black}{green}{white}{blue}}
\begin{document}
\setbox\stereogrambox=\hbox{%
	\begin{tikzpicture}[x=1/2pt,y=1/2pt]
		\foreach \x in {0,...,95}
		\foreach \y in {0,...,119}{
				\pgfmathrandomitem\c{colors}
				\fill [fill=\c] (\x,\y) rectangle ++(1,1);
			}
	\end{tikzpicture}}%
\begin{tikzpicture}[x=1pt,y=1pt,
		stereogram node/.style={inner sep=0, outer sep=0,
				anchor=south, fill=white, execute at begin node=\copy\stereogrambox
			}]
	\foreach \x in {0,...,1}
	\node [stereogram node] at (\x*52, 0) {};
	\clip [shift={(0, 4)}]
	(0,0) -- (-4,0) -- (-4,4) -- (-18,4) -- (0,52) --
	(18,4) -- (4,4) -- (4,0) -- cycle;
	\node [stereogram node] at (2, 0) {};
\end{tikzpicture}
\end{document}

enter image description here
